Photographic developing method and apparatus



Jan. 11, 1949. w. D. ROSE 2,458,877

PHOTOGRAPHIC DEVELOPING METHOD AND APPARATUS Filed Sept. 7, 1946 ROLLERsqussazz ROLLER Patented Jan. 11 1949 PHOTOGRAPHIC DEVELOPING METHOD ANDAPPARATUS Walter Dean Rose, Tulsa, Okla., assignor to Standard OilDevelopment Company, a corporation of Delaware Application September 7,1946, Serial No. 695,527

3 Claims. 1

The present invention is directed to a method and apparatus fordeveloping images on sensitized paper or film.

There are many operations in which it is desired to produce quickly apermanent record of some value undergoing change. Typical cases arefound in the art of oil prospecting and well logging. In oil prospectingby the seismic method seismic waves reflected from the subsurface arepicked up at the surface, converted into electrical quantities andrecorded conventionally by the use of a recording galvanometer. Thisprocedure produces on a film or sensitized paper a latent image of therecord which must then be developed to render it visible. The ordinaryphotographic developing procedure involves chemical developing, fixing,washing and drying. This operation requires a period varying fromseveral minutes to perhaps an hour, depending upon various conditions.

vIn like manner, in the electric logging of wells there is produced atrace or traces on a sensitized strip by recording galvanometer. Again,the development of this trace requires the operations above enumeratedwith the consequent time consumption.

The principal object of the present invention is the provision of amethod and apparatus primarily intended for field use in operations ofthe type above referred to which produce a developed record stripcontinuously as rapidly as the recording is made.

An additional object of the present invention is the provision of anapparatus of the type indicated which is simple, inexpensive andfoolproof in operation.

Briefly, the method of the present invention comprises dipping theexposed film or sensitized paper in a solution of a special electrolyticdeveloping solution and then pressing the exposed film surface against asmooth, clean surface composed of a metal occurring higher in theelectromotive series than silver. The most convenient metal and the mosteffective one for this purpose is copper. Excellent results are securedby using a dilute solution of ammonium hydroxide in water; for example,about a 2% solution, as the electrolyte. A better definition of theimage is secured if a minute quantity of a mercury salt is incorporatedin the solution of electrolyte. A preferred formula for the electrolytesolution is:

28% NH40H ccs 40 Formaldehyde ccs 5 H2O ccs 2000 HgClz gms 0.5

The nature and objects of the present invention will be more clearlyunderstood from the following detailed description of the accompanyingdrawing in which the single figure is a vertical section of one type ofsuitable apparatus.

Referring to the drawing in detail, numeral I indicates a camera boxprovided with a reel of film or sensitized paper 2 which is fed over aseries of rollers by feed rolls 3 which eject the developed record fromthe box. The recording strip passes from the reel over a roller 4 withits sensitized surface exposed to a lens 5 through which the value to berecorded is focused on the sensitized strip. The record strip passesfrom roller 4 over a roller 6 partly immersed in a solution 1 of anelectrolyte contained in tank 8. From roller 6 the sensitized strip isthreaded over a roller 9, the surface of which is composed of orcontains a metal higher in the electromotive series than silver. Aconvenient material of which to compose this roller is brass. In firmcontact with the roller 9 is a squeegee roller [0 which serves to dryoff or remove any moisture contained on the record strip. It will beobserved that the sensitized side of the strip is exposed in turn to theelectrolyte and then brought into close contact with the surface of theroller 9. In order to insure good contact the device is operated so thatthe strip is taut between rollers 6 and 9.

The present invention also contemplates the employment of the copper orother metal of the type indicated in finely divided powder form as aslurry in the electrolyte 1.

In this embodiment, roller 9 need not be composed of such metal but mayform with roller 10 merely a squeegeeing and drying means.

The present invention also contemplates the employment of stationarybars or shims of brass or other metal of the type indicated which can bearranged in the path of the strip in such a way that the strip ispressed thereon. In other words,

3 instead of roller 9 there can be employed a stationary bar or shim ofmetal.

The present invention also contemplates the use of a silver halide typelight-sensitive emulsion paper, the emulsion and paper base of which areimpregnated with copper or other suitable metal powder. In thisembodiment, development of the exposed strip merely involves immersionof the strip in the above described electrolyte developing solution andthen in a dilute acid bath so that the development will cease before thefilm strip is ejected from the light-tight camera box.

The time of contact of the exposed sensitized surface With theelectrolyte and with the copper or other metal need not be more thaninstantaneous, that is to say, there is no time lag involved in thisoperation. As a consequence,-the developed film is fed out of the cameraas rapidly as the desired value is recorded upon it and comes outsufficiently dry to be handled immediately. This constitutes a verysubstantial advantage in operations of the aforesaid'type becauseoftenchanges in technique are indicated to be desirable by the characterof the record being produced and the sooner the operator can ascertainthe desirability of such changev in technique the more reflectivebecomes the operation.

In addition, no thermal control is necessary for the practice of theprocess of the present invention. The need-for an elaborate dark roomis-eliminated. Furthermore, the operator need possess-no 'skillinphotographic processes. All of these advantages are of extremeimportance in field work where simplicity and operability by thosehaving no special skill are attractive features.

The nature and objects of the present invention having been thusdescribed and illustrated, what is claimed as new and useful and isdesired to be secured by Letters Patent is:

1. A method for producin a permanent image on a sensitized stripcontaining a silver halide emulsion which comprises continuouslyexposing the emulsion side of thestrip to a beam of light, continuouslycontacting the exposedemulsion side of the strip with an aqueoussolution of ammonia and contacting :the electrolyte-wet surface with 4copper while simultaneously removing excess solution from said strip.

2. An apparatus for making continuous records comprising a reel carryinga silver halide emulsion, means for exposing the emulsion to a beam oflight representing the value to be recorded, means for passing theexposed emulsion into contact with an aqueous solution of ammonia, meansfor pressing the electrolyte wet surface against a plate of copper andmeans for removing excess solution from said surface.

3. The method according to claim 1 in which the aqueous solution ofammonia contains a minute quantity of a soluble mercury salt.

WALTER DEAN ROSE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,653,429 Caps Dec. 20, 19271,742,710 Krebs Jan. '7, 1930 2,176,000 Albano Oct. 10, 1939 2,196,133Webb Apr. 2, 1940 234255.49 "Christaldi 'Mar. 28, 1944 2,405,090 GrouseJuly 30, 1946 2,409,959 Ryan"-.. Oct. 22, 1946 OTHER REFERENCES Fuchs,"-Entwicklung Photographischer Schichten auf Electrischem WegePhotographische Industrie, vol. 28, 1930, pages 927 and 928 cited. (Copyin S. L.)

'Kellner, Studien uber die Elektrolytische Entwicklung PhotographischerSchichten, Zeitschrift'fur Wissenschaftliche Photographic. Bd 33 Heft 9,1935, pages 212 to 224, pages 219 to 221 cited. (Copy in Div. 67.)

Sheppard, Electrochemical Aspects of Photographic Developmen Trans. Am.Elect. Soc, Vol. 39, 192-1, pages 429 to 440, pages 430'to 432 cited.(Copy in S. L.)

Mees, The Theory of the Photographic Process, The MacMillan Co., 1942,page 333 cited. (Copy in Div. 67.)

